Within the _CDM model, we studied dynamical aspects of the universe in SdS spacetime background.rnMainly, the precession of orbits from solar-planetary to binary galaxy, the effect of geometry in radiallyrnfalling particles to massive compacts and the gravitational deflection of light by extended sources. UsingrnEinstein field equations and conservation laws, equation of motion and the general effective potential in SdSrnwere derived. The potential has used in the characterization of the orbits, where hypothetical potential sourcesrnranging from small mass to critical black holes were used. The sample orbiters cover both massive and masslessrnparticles with and without angular momentum. Generally, SdS potential differs from the Schwarzschildrnpotential. Moreover, the potential has used to derive important boundary conditions in the motion of thernparticles. Specially, it has used to derive photon orbit and radial solution of closed circular orbits of massivernparticles. Taking into account the positions of the source, lens and observer the photon orbit solution used tornderive the gravitational bending angle; where it has in turn used in gravitational lensing to estimate the mass ofrnthe lensing where _ effect was of order 2% relative to the Schwarzschild background. In the case of circularrnorbits, the radial deviation has studied, where the effect was insignificant at small-scale, within Milky-Wayrngalaxy; but at binary galaxy level becomes viable, kpc to Mpc order. For the case of elliptical orbits, arntwo-body problem has developed to derive the precession. _ effect was dominant over the Schwarzschildrnin open and wide systems like binary galaxy, but insignificant in others. _ has significant effect comparedrnto the Schwarzschild case on radiations from in falling particles to massive objects if appreciable distancesrnare considered. Finally, we have reflected our views regarding the criticisms on Einstein modified field equations,rnattributed to the cosmological constant. A detailed review with some supplementary works presentedrnto enrich the relevance of the cosmological constant as an intrinsic constant.